1. Field of the Invention
This invention relates to a thin-wall plain sleeve bearing of the type having an oil film or layer between the bearing surface and a journaled member. The invention is particularly applicable to half-shell sleeve bearings used in internal combustion engines in cooperation with crank shafts and connecting rods. However, it will be appreciated that the invention has broader application and may be used in other environments of this general type, e.g., main bearings.
2. Description of the Prior Art
Sleeve bearings of the type to which the subject invention relate have a cylindrical outer surface or O.D. commonly called the bearing back which is disposed in a housing such as at the end of a connecting rod. Such sleeve bearings include an inner bearing surface in varying engagement with a journaled member such as a journaled portion of a crank shaft. The members forming the bearing housing are in clamping engagement with the bearing back to apply radial forces to the bearing back and the bearing assembly is continuously subjected to an oil supply for establishing a film of oil between the bearing surface and the journaled member.
The outer cylindrical surface defining the bearing back and the inner bearing surface in such sleeve bearings extend axially between opposite ends of the bearing and circumferentially 360.degree. with the sleeve bearing being defined by two half shells having parting faces in abutting engagement with one another. Because of the various procedures used to manufacture the bearing half shells, the profile of the bearing back or outer cylindrical surface will be generally concave axially between opposite ends of the bearing. The amount of the concavity will vary from bearing to bearing as a result of the size of the bearing, the material thickness, etc.; however, the bearing back is basically always concave between the ends when the bearing is in the free state and when held to gage diameter, i.e., not clamped in a bearing housing. Further, the bearing backs normally include a very thin protective coating or plating, such as flash lead or tin.